Abstract

Background: DNA integrity analysis could represent an alternative approach to the early detection of colorectal cancer (CRC). Previously, fluorescence long DNA (FL-DNA) in stools was extracted using a manual approach and analysed by capillary electrophoresis assay (CE FL-DNA). We aimed to improve diagnostic accuracy using a simpler and more standardised method (Real Time PCR FL-DNA [RT FL-DNA]) for the detection of early malignant lesions in a population undergoing CRC screening.
Methods: From 241 stool samples, DNA was extracted using manual and semi-automatic extraction systems and analysed using FL-DNA tests by CE and RT assays. The RT FL-DNA approach showed slightly higher sensitivity and specificity compared to the CE FL-DNA method. Furthermore, we compared the RT FL-DNA approach with the iFOBT report.
Results: Non-parametric ranking statistics were used to analyse the relationship between the median values of RT FL-DNA and the clinico-histopathological characteristics. The median values of both variables were significantly higher in cancer patients than in patients with non-cancerous lesions. According to the Fagan nomogram results, iFOBT and FL-DNA methods provided more accurate diagnostic information and were able to identify subgroups at varying risks of cancer.
Conclusions: The combination of the semi-automatic extraction system and RT FL-DNA analysis improved the quality of DNA extracted from stool samples.
Impact: RT FL-DNA shows great potential for colorectal cancer diagnosis as it is a reliable and relatively easy analysis to perform on routinely processed stool samples in combination with iFOBT.